1. Field of the Invention
This invention relates to a chemical analysis apparatus provided with an incubator having a plurality of chambers on the same circumference.
2. Description of the Prior Art
In general, it is often desired to investigate whether a specific constituent is or is not contained in a liquid sample such as blood or blood serum or to investigate the contents of specific constituents in the liquid sample. For this purpose, chemical analysis using a reaction reagent is carried out. The chemical analysis methods for liquid samples are classified into a dry method and a wet method. In the dry method, a sample solution is analyzed by use of a chemical analysis slide having a reagent layer impregnated with a predetermined reagent. Specifically, a measured amount of a sample solution is put on the reagent layer of the chemical analysis slide and is maintained at a predetermined temperature (i.e., incubated) for a predetermined time in an incubator to cause a color reaction, the chemical analysis slide is exposed to measuring light having a wavelength selected in advance in accordance with the combination of the sample constituent with a reagent contained in the reagent layer of the chemical analysis slide, and the optical density in terms of the light reflected by the chemical analysis slide is measured In this manner, quantitative analysis of the chemical analysis constituent or the like is carried out.
In medical organizations, research laboratories or the like in which many sample solutions are to be analyzed, it is desired that the analysis be carried out automatically and continuously. To satisfy this need, there have been proposed various chemical analysis apparatuses for carrying out sample analysis automatically and continuously by use of the aforesaid chemical analysis slides.
For example, it has been proposed in Japanese Unexamined Patent Publication No. 60(1985)-57259 to constitute a chemical analysis apparatus so that a disk on which a plurality of chemical analysis slides are disposed in an equally spaced relation to each other on the same circumference is housed for a predetermined time in a pre-heating chamber of an incubator, the pre-heated disk is moved to a measurement chamber of the incubator and incubated therein, a necessary amount of a sample solution is applied by use of a pipette onto the chemical analysis slides while they are being incubated, and measurement of the optical density in terms of the reflected light is carried out by rotating the disk and closely contacting the respective chemical analysis slides one after another with a probe. After the measurement is finished for all of the chemical analysis slides, the disk is taken out of the measurement chamber, a disk on which chemical analysis slides without a sample solution applied thereon are disposed and which has been pre-heated in the pre-heating chamber is fed into the measurement chamber, and the aforesaid operations are repeated.
However, since it is necessary that sample analysis be carried out continuously and rationally as mentioned above, a need exists for a more automatic and rational method of sample analysis.
Particularly in the case where rate measurement is to be carried out after carrying out background measurement for each of a plurality of the chemical analysis slides by use of a single probe, besides irradiation of the measuring light for the background measurement and the rate measurement, it is necessary to carry out feeding of the chemical analysis slides into and ejection thereof from the chambers of the incubator, application of a sample solution or the like. A long time is required for the respective operations, and it is not always possible to carry out rate measurement of the respective chemical analysis slides at short intervals. Accordingly, a need exists for a chemical analysis apparatus which can perform the respective operations quickly and efficiently.
By the term "background measurement" as used herein is meant the measurement of the optical reflection density of the chemical analysis slide without a sample solution applied thereon, which is carried out for discriminating whether or not the chemical analysis slide is acceptable for rate measurement or for compensation of the optical reflection density measured after a color reaction is effected on the chemical analysis slide.
By the term "rate measurement" as used herein is meant the measurement of a change rate of the optical reflection density by measuring the optical reflection density a plurality of times for a single chemical analysis slide at short time intervals within the range of, for example, 5 to 10 seconds. When the time interval is long, the accuracy of the rate measurement is deteriorated.